As I blogged about earlier this week, http://outdoornebraska.ne.gov/blogs/2012/03/news-items-march-28-2012/ , our field crews began collecting walleye eggs this week. Let me give you an update on how that annual project is progressing as of this morning.
We started collecting spawning walleyes at Sherman Reservoir last Monday, March 26 and we started collecting spawners at Merritt Reservoir on Wednesday, March 28. Our crews have been collecting a lot of male and female walleyes, but so far almost 75% of those females are still what we refer to as “green”–in other words the females are full of eggs, but not quite ready to deposit them yet. That brings up an interesting point, I always say that the walleyes in most Nebraska reservoirs spawn April 1. I say that because I believe the amount of daylight or photoperiod is one of the most important cues that triggers spawning behavior in the species of fish found in Nebraska. Water temperature and weather can be other cues that trigger spawning, but I believe they are less important and only modify the annual spawning period.
If there was ever a year to test my belief about photoperiod being the most important cue for the walleye spawn it is this year. Our weather in March has been unbelievably warm and mild, and if there was ever a year for the walleyes to spawn “early”, it would have been this year. Our crews started collecting walleye spawners about a week earlier than originally planned because of the weather, but we are finding that almost 75% of the female walleyes collected so far are not quite ready yet–just a few more days. So, there you go, the walleye spawn on most Nebraska reservoirs is about April 1.
When our crews collect female walleyes that are not quite ready to give up their eggs, we will hold those green fish for up to 3 days in cribs, holding nets. We will eventually collect eggs from most of those cribbed, green females before they are released after 3 days at the longest (when we collect eggs from a female walleye, she is then immediately released, none are held in the cribs longer than 3 days). Our crews have collected a lot of female walleyes this week, well over 600 and we have already collected over half of the total eggs needed to fill all of our walleye stocking requests for this year. Our total goal, total number of eggs needed to produce all the walleyes to be stocked this year, is just less than 600 quarts of eggs. If you want to play with some numbers that would equal approximately 72 million walleye eggs, and even though that seems like a lot, it represents less than 5%, in most cases a lot less than 5%, of the total egg production of the walleye populations in the waters from which we collect those eggs.
Here are our plans for the rest of the walleye egg collections. The crews will continue to collect fish at Sherman and Merritt reservoirs tonight. We have collected a lot of walleye eggs in a short amount of time and need to spread out the hatching of those eggs in the hatcheries, so after tonight the collection crews will back off, and get a much needed break, for a couple of nights. Egg collection activities will gear up again next week, on Monday weather permitting, and we plan to collect some walleye eggs from McConaughy next week as well.
We like to utilize several resevoirs for our walleye egg collections because, if you will pardon the pun, it is a good idea NOT to put all of our eggs in one basket. Even though the walleye population in just one reservoir could easily produce all the eggs needed to meet all of our stocking requests, we like to utilize at least a couple, three reservoirs just in case there is a problem with the eggs from one reservoir, and it gives us more flexibility in hatching dates and walleye production schedules in the hatcheries.
I anticipate that we will complete our annual walleye egg collections next week with no problem. But, ultimately, the walleyes and the weather determine how that is going to play out, so stay tuned. . . .
If you want some more details on the entire walleye egg collection process, here is an excellent video that was produced a couple of years ago.
There is no doubt about it, spring is in the air, and in the water!